/*
 *  SSL client with certificate authentication
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf     printf
#define mbedtls_fprintf    fprintf
#define mbedtls_snprintf   snprintf
#endif

#if !defined(MBEDTLS_ENTROPY_C) || \
	!defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_CLI_C) || \
	!defined(MBEDTLS_NET_C) || !defined(MBEDTLS_CTR_DRBG_C)
int main( void )
{
	mbedtls_printf("MBEDTLS_ENTROPY_C and/or "
		   "MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_CLI_C and/or "
		   "MBEDTLS_NET_C and/or MBEDTLS_CTR_DRBG_C and/or not defined.\n");
	return( 0 );
}
#else

#include "mbedtls/net.h"
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/certs.h"
#include "mbedtls/x509.h"
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
#include "mbedtls/timing.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define DFL_SERVER_NAME         "server"
#define DFL_SERVER_ADDR         "192.168.43.4"
#define DFL_SERVER_PORT         "4433"
#define DFL_REQUEST_PAGE        "/"
#define DFL_REQUEST_SIZE        -1
#define DFL_DEBUG_LEVEL         0
#define DFL_NBIO                0
#define DFL_READ_TIMEOUT        0
#define DFL_MAX_RESEND          0
#define DFL_CA_FILE             ""
#define DFL_CA_PATH             ""
#define DFL_CRT_FILE            ""
#define DFL_KEY_FILE            ""
#define DFL_PSK                 ""
#define DFL_PSK_IDENTITY        "Client_identity"
#define DFL_ECJPAKE_PW          NULL
#define DFL_FORCE_CIPHER        0
#define DFL_RENEGOTIATION       MBEDTLS_SSL_RENEGOTIATION_DISABLED
#define DFL_ALLOW_LEGACY        -2
#define DFL_RENEGOTIATE         0
#define DFL_EXCHANGES           1
#define DFL_MIN_VERSION         -1
#define DFL_MAX_VERSION         -1
#define DFL_ARC4                -1
#define DFL_AUTH_MODE           -1
#define DFL_MFL_CODE            MBEDTLS_SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC          -1
#define DFL_RECSPLIT            -1
#define DFL_DHMLEN              -1
#define DFL_RECONNECT           0
#define DFL_RECO_DELAY          0
#define DFL_RECONNECT_HARD      0
#define DFL_TICKETS             MBEDTLS_SSL_SESSION_TICKETS_ENABLED
#define DFL_ALPN_STRING         NULL
#define DFL_TRANSPORT           MBEDTLS_SSL_TRANSPORT_STREAM
#define DFL_HS_TO_MIN           0
#define DFL_HS_TO_MAX           0
#define DFL_FALLBACK            -1
#define DFL_EXTENDED_MS         -1
#define DFL_ETM                 -1

#define GET_REQUEST "GET %s HTTP/1.0\r\nExtra-header: "
#define GET_REQUEST_END "\r\n\r\n"

#if defined(MBEDTLS_X509_CRT_PARSE_C)
#if defined(MBEDTLS_FS_IO)
#define USAGE_IO \
	"    ca_file=%%s          The single file containing the top-level CA(s) you fully trust\n" \
	"                        default: \"\" (pre-loaded)\n" \
	"    ca_path=%%s          The path containing the top-level CA(s) you fully trust\n" \
	"                        default: \"\" (pre-loaded) (overrides ca_file)\n" \
	"    crt_file=%%s         Your own cert and chain (in bottom to top order, top may be omitted)\n" \
	"                        default: \"\" (pre-loaded)\n" \
	"    key_file=%%s         default: \"\" (pre-loaded)\n"
#else
#define USAGE_IO \
	"    No file operations available (MBEDTLS_FS_IO not defined)\n"
#endif /* MBEDTLS_FS_IO */
#else
#define USAGE_IO ""
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
#define USAGE_PSK                                                   \
	"    psk=%%s              default: \"\" (in hex, without 0x)\n" \
	"    psk_identity=%%s     default: \"Client_identity\"\n"
#else
#define USAGE_PSK ""
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
#define USAGE_TICKETS                                       \
	"    tickets=%%d          default: 1 (enabled)\n"
#else
#define USAGE_TICKETS ""
#endif /* MBEDTLS_SSL_SESSION_TICKETS */

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
#define USAGE_TRUNC_HMAC                                    \
	"    trunc_hmac=%%d       default: library default\n"
#else
#define USAGE_TRUNC_HMAC ""
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
#define USAGE_MAX_FRAG_LEN                                      \
	"    max_frag_len=%%d     default: 16384 (tls default)\n"   \
	"                        options: 512, 1024, 2048, 4096\n"
#else
#define USAGE_MAX_FRAG_LEN ""
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
#define USAGE_RECSPLIT \
	"    recsplit=0/1        default: (library default: on)\n"
#else
#define USAGE_RECSPLIT
#endif

#if defined(MBEDTLS_DHM_C)
#define USAGE_DHMLEN \
	"    dhmlen=%%d           default: (library default: 1024 bits)\n"
#else
#define USAGE_DHMLEN
#endif

#if defined(MBEDTLS_SSL_ALPN)
#define USAGE_ALPN \
	"    alpn=%%s             default: \"\" (disabled)\n"   \
	"                        example: spdy/1,http/1.1\n"
#else
#define USAGE_ALPN ""
#endif /* MBEDTLS_SSL_ALPN */

#if defined(MBEDTLS_SSL_PROTO_DTLS)
#define USAGE_DTLS \
	"    dtls=%%d             default: 0 (TLS)\n"                           \
	"    hs_timeout=%%d-%%d    default: (library default: 1000-60000)\n"    \
	"                        range of DTLS handshake timeouts in millisecs\n"
#else
#define USAGE_DTLS ""
#endif

#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
#define USAGE_FALLBACK \
	"    fallback=0/1        default: (library default: off)\n"
#else
#define USAGE_FALLBACK ""
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
#define USAGE_EMS \
	"    extended_ms=0/1     default: (library default: on)\n"
#else
#define USAGE_EMS ""
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
#define USAGE_ETM \
	"    etm=0/1             default: (library default: on)\n"
#else
#define USAGE_ETM ""
#endif

#if defined(MBEDTLS_SSL_RENEGOTIATION)
#define USAGE_RENEGO \
	"    renegotiation=%%d    default: 0 (disabled)\n"      \
	"    renegotiate=%%d      default: 0 (disabled)\n"
#else
#define USAGE_RENEGO ""
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
#define USAGE_ECJPAKE \
	"    ecjpake_pw=%%s       default: none (disabled)\n"
#else
#define USAGE_ECJPAKE ""
#endif

#define USAGE \
	"\n usage: ssl_client2 param=<>...\n"                   \
	"\n acceptable parameters:\n"                           \
	"    server_name=%%s      default: localhost\n"         \
	"    server_addr=%%s      default: given by name\n"     \
	"    server_port=%%d      default: 4433\n"              \
	"    request_page=%%s     default: \".\"\n"             \
	"    request_size=%%d     default: about 34 (basic request)\n" \
	"                        (minimum: 0, max: 16384)\n" \
	"    debug_level=%%d      default: 0 (disabled)\n"      \
	"    nbio=%%d             default: 0 (blocking I/O)\n"  \
	"                        options: 1 (non-blocking), 2 (added delays)\n" \
	"    read_timeout=%%d     default: 0 ms (no timeout)\n"    \
	"    max_resend=%%d       default: 0 (no resend on timeout)\n" \
	"\n"                                                    \
	USAGE_DTLS                                              \
	"\n"                                                    \
	"    auth_mode=%%s        default: (library default: none)\n"      \
	"                        options: none, optional, required\n" \
	USAGE_IO                                                \
	"\n"                                                    \
	USAGE_PSK                                               \
	USAGE_ECJPAKE                                           \
	"\n"                                                    \
	"    allow_legacy=%%d     default: (library default: no)\n"      \
	USAGE_RENEGO                                            \
	"    exchanges=%%d        default: 1\n"                 \
	"    reconnect=%%d        default: 0 (disabled)\n"      \
	"    reco_delay=%%d       default: 0 seconds\n"         \
	"    reconnect_hard=%%d   default: 0 (disabled)\n"      \
	USAGE_TICKETS                                           \
	USAGE_MAX_FRAG_LEN                                      \
	USAGE_TRUNC_HMAC                                        \
	USAGE_ALPN                                              \
	USAGE_FALLBACK                                          \
	USAGE_EMS                                               \
	USAGE_ETM                                               \
	USAGE_RECSPLIT                                          \
	USAGE_DHMLEN                                            \
	"\n"                                                    \
	"    arc4=%%d             default: (library default: 0)\n" \
	"    min_version=%%s      default: (library default: tls1)\n"       \
	"    max_version=%%s      default: (library default: tls1_2)\n"     \
	"    force_version=%%s    default: \"\" (none)\n"       \
	"                        options: ssl3, tls1, tls1_1, tls1_2, dtls1, dtls1_2\n" \
	"\n"                                                    \
	"    force_ciphersuite=<name>    default: all enabled\n"\
	" acceptable ciphersuite names:\n"

/*
 * global options
 */
struct options
{
	const char *server_name;    /* hostname of the server (client only)     */
	const char *server_addr;    /* address of the server (client only)      */
	const char *server_port;    /* port on which the ssl service runs       */
	int debug_level;            /* level of debugging                       */
	int nbio;                   /* should I/O be blocking?                  */
	uint32_t read_timeout;      /* timeout on mbedtls_ssl_read() in milliseconds    */
	int max_resend;             /* DTLS times to resend on read timeout     */
	const char *request_page;   /* page on server to request                */
	int request_size;           /* pad request with header to requested size */
	const char *ca_file;        /* the file with the CA certificate(s)      */
	const char *ca_path;        /* the path with the CA certificate(s) reside */
	const char *crt_file;       /* the file with the client certificate     */
	const char *key_file;       /* the file with the client key             */
	const char *psk;            /* the pre-shared key                       */
	const char *psk_identity;   /* the pre-shared key identity              */
	const char *ecjpake_pw;     /* the EC J-PAKE password                   */
	int force_ciphersuite[2];   /* protocol/ciphersuite to use, or all      */
	int renegotiation;          /* enable / disable renegotiation           */
	int allow_legacy;           /* allow legacy renegotiation               */
	int renegotiate;            /* attempt renegotiation?                   */
	int renego_delay;           /* delay before enforcing renegotiation     */
	int exchanges;              /* number of data exchanges                 */
	int min_version;            /* minimum protocol version accepted        */
	int max_version;            /* maximum protocol version accepted        */
	int arc4;                   /* flag for arc4 suites support             */
	int auth_mode;              /* verify mode for connection               */
	unsigned char mfl_code;     /* code for maximum fragment length         */
	int trunc_hmac;             /* negotiate truncated hmac or not          */
	int recsplit;               /* enable record splitting?                 */
	int dhmlen;                 /* minimum DHM params len in bits           */
	int reconnect;              /* attempt to resume session                */
	int reco_delay;             /* delay in seconds before resuming session */
	int reconnect_hard;         /* unexpectedly reconnect from the same port */
	int tickets;                /* enable / disable session tickets         */
	const char *alpn_string;    /* ALPN supported protocols                 */
	int transport;              /* TLS or DTLS?                             */
	uint32_t hs_to_min;         /* Initial value of DTLS handshake timer    */
	uint32_t hs_to_max;         /* Max value of DTLS handshake timer        */
	int fallback;               /* is this a fallback connection?           */
	int extended_ms;            /* negotiate extended master secret?        */
	int etm;                    /* negotiate encrypt then mac?              */
} opt;

static void my_debug( void *ctx, int level,
					  const char *file, int line,
					  const char *str )
{
	const char *p, *basename;

	/* Extract basename from file */
	for( p = basename = file; *p != '\0'; p++ )
		if( *p == '/' || *p == '\\' )
			basename = p + 1;

	mbedtls_fprintf( (FILE *) ctx, "%s:%04d: |%d| %s", basename, line, level, str );
	fflush(  (FILE *) ctx  );
}

/*
 * Test recv/send functions that make sure each try returns
 * WANT_READ/WANT_WRITE at least once before sucesseding
 */
static int my_recv( void *ctx, unsigned char *buf, size_t len )
{
	static int first_try = 1;
	int ret;

	if( first_try )
	{
		first_try = 0;
		return( MBEDTLS_ERR_SSL_WANT_READ );
	}

	ret = mbedtls_net_recv( ctx, buf, len );
	if( ret != MBEDTLS_ERR_SSL_WANT_READ )
		first_try = 1; /* Next call will be a new operation */
	return( ret );
}

static int my_send( void *ctx, const unsigned char *buf, size_t len )
{
	static int first_try = 1;
	int ret;

	if( first_try )
	{
		first_try = 0;
		return( MBEDTLS_ERR_SSL_WANT_WRITE );
	}

	ret = mbedtls_net_send( ctx, buf, len );
	if( ret != MBEDTLS_ERR_SSL_WANT_WRITE )
		first_try = 1; /* Next call will be a new operation */
	return( ret );
}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
/*
 * Enabled if debug_level > 1 in code below
 */
static int my_verify( void *data, mbedtls_x509_crt *crt, int depth, uint32_t *flags )
{
	char buf[1024];
	((void) data);

	mbedtls_printf( "\nVerify requested for (Depth %d):\n", depth );
	mbedtls_x509_crt_info( buf, sizeof( buf ) - 1, "", crt );
	mbedtls_printf( "%s", buf );

	if ( ( *flags ) == 0 )
		mbedtls_printf( "  This certificate has no flags\n" );
	else
	{
		mbedtls_x509_crt_verify_info( buf, sizeof( buf ), "  ! ", *flags );
		mbedtls_printf( "%s\n", buf );
	}

	return( 0 );
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

mbedtls_net_context server_fd;
unsigned char buf[MBEDTLS_SSL_MAX_CONTENT_LEN + 1];
#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
unsigned char psk[MBEDTLS_PSK_MAX_LEN];
size_t psk_len = 0;
#endif
#if defined(MBEDTLS_SSL_ALPN)
const char *alpn_list[10];
#endif
const char *pers = "ssl_client2";
mbedtls_entropy_context entropy;
mbedtls_ctr_drbg_context ctr_drbg;
mbedtls_ssl_context ssl;
mbedtls_ssl_config conf;
mbedtls_ssl_session saved_session;
#if defined(MBEDTLS_TIMING_C)
mbedtls_timing_delay_context timer;
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
uint32_t flags;
mbedtls_x509_crt cacert;
mbedtls_x509_crt clicert;
mbedtls_pk_context pkey;
#endif

int main( int argc, char *argv[] )
{
	int ret = 0, len, tail_len, i, written, frags, retry_left;
	char *p, *q;
	const int *list;

	/*
	 * Make sure memory references are valid.
	 */
	mbedtls_net_init( &server_fd );
	mbedtls_ssl_init( &ssl );
	mbedtls_ssl_config_init( &conf );
	memset( &saved_session, 0, sizeof( mbedtls_ssl_session ) );
	mbedtls_ctr_drbg_init( &ctr_drbg );
#if defined(MBEDTLS_X509_CRT_PARSE_C)
	mbedtls_x509_crt_init( &cacert );
	mbedtls_x509_crt_init( &clicert );
	mbedtls_pk_init( &pkey );
#endif
#if defined(MBEDTLS_SSL_ALPN)
	memset( (void * ) alpn_list, 0, sizeof( alpn_list ) );
#endif

	if( argc == 0 )
	{
	usage:
		if( ret == 0 )
			ret = 1;

		mbedtls_printf( USAGE );

		list = mbedtls_ssl_list_ciphersuites();
		while( *list )
		{
			mbedtls_printf(" %-42s", mbedtls_ssl_get_ciphersuite_name( *list ) );
			list++;
			if( !*list )
				break;
			mbedtls_printf(" %s\n", mbedtls_ssl_get_ciphersuite_name( *list ) );
			list++;
		}
		mbedtls_printf("\n");
		goto exit;
	}

	opt.server_name         = DFL_SERVER_NAME;
	opt.server_addr         = DFL_SERVER_ADDR;
	opt.server_port         = DFL_SERVER_PORT;
	opt.debug_level         = DFL_DEBUG_LEVEL;
	opt.nbio                = DFL_NBIO;
	opt.read_timeout        = DFL_READ_TIMEOUT;
	opt.max_resend          = DFL_MAX_RESEND;
	opt.request_page        = DFL_REQUEST_PAGE;
	opt.request_size        = DFL_REQUEST_SIZE;
	opt.ca_file             = DFL_CA_FILE;
	opt.ca_path             = DFL_CA_PATH;
	opt.crt_file            = DFL_CRT_FILE;
	opt.key_file            = DFL_KEY_FILE;
	opt.psk                 = DFL_PSK;
	opt.psk_identity        = DFL_PSK_IDENTITY;
	opt.ecjpake_pw          = DFL_ECJPAKE_PW;
	opt.force_ciphersuite[0]= DFL_FORCE_CIPHER;
	opt.renegotiation       = DFL_RENEGOTIATION;
	opt.allow_legacy        = DFL_ALLOW_LEGACY;
	opt.renegotiate         = DFL_RENEGOTIATE;
	opt.exchanges           = DFL_EXCHANGES;
	opt.min_version         = DFL_MIN_VERSION;
	opt.max_version         = DFL_MAX_VERSION;
	opt.arc4                = DFL_ARC4;
	opt.auth_mode           = DFL_AUTH_MODE;
	opt.mfl_code            = DFL_MFL_CODE;
	opt.trunc_hmac          = DFL_TRUNC_HMAC;
	opt.recsplit            = DFL_RECSPLIT;
	opt.dhmlen              = DFL_DHMLEN;
	opt.reconnect           = DFL_RECONNECT;
	opt.reco_delay          = DFL_RECO_DELAY;
	opt.reconnect_hard      = DFL_RECONNECT_HARD;
	opt.tickets             = DFL_TICKETS;
	opt.alpn_string         = DFL_ALPN_STRING;
	opt.transport           = DFL_TRANSPORT;
	opt.hs_to_min           = DFL_HS_TO_MIN;
	opt.hs_to_max           = DFL_HS_TO_MAX;
	opt.fallback            = DFL_FALLBACK;
	opt.extended_ms         = DFL_EXTENDED_MS;
	opt.etm                 = DFL_ETM;

	for( i = 1; i < argc; i++ )
	{
		p = argv[i];
		if( ( q = strchr( p, '=' ) ) == NULL )
			goto usage;
		*q++ = '\0';

		if( strcmp( p, "server_name" ) == 0 )
			opt.server_name = q;
		else if( strcmp( p, "server_addr" ) == 0 )
			opt.server_addr = q;
		else if( strcmp( p, "server_port" ) == 0 )
			opt.server_port = q;
		else if( strcmp( p, "dtls" ) == 0 )
		{
			int t = atoi( q );
			if( t == 0 )
				opt.transport = MBEDTLS_SSL_TRANSPORT_STREAM;
			else if( t == 1 )
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			else
				goto usage;
		}
		else if( strcmp( p, "debug_level" ) == 0 )
		{
			opt.debug_level = atoi( q );
			if( opt.debug_level < 0 || opt.debug_level > 65535 )
				goto usage;
		}
		else if( strcmp( p, "nbio" ) == 0 )
		{
			opt.nbio = atoi( q );
			if( opt.nbio < 0 || opt.nbio > 2 )
				goto usage;
		}
		else if( strcmp( p, "read_timeout" ) == 0 )
			opt.read_timeout = atoi( q );
		else if( strcmp( p, "max_resend" ) == 0 )
		{
			opt.max_resend = atoi( q );
			if( opt.max_resend < 0 )
				goto usage;
		}
		else if( strcmp( p, "request_page" ) == 0 )
			opt.request_page = q;
		else if( strcmp( p, "request_size" ) == 0 )
		{
			opt.request_size = atoi( q );
			if( opt.request_size < 0 || opt.request_size > MBEDTLS_SSL_MAX_CONTENT_LEN )
				goto usage;
		}
		else if( strcmp( p, "ca_file" ) == 0 )
			opt.ca_file = q;
		else if( strcmp( p, "ca_path" ) == 0 )
			opt.ca_path = q;
		else if( strcmp( p, "crt_file" ) == 0 )
			opt.crt_file = q;
		else if( strcmp( p, "key_file" ) == 0 )
			opt.key_file = q;
		else if( strcmp( p, "psk" ) == 0 )
			opt.psk = q;
		else if( strcmp( p, "psk_identity" ) == 0 )
			opt.psk_identity = q;
		else if( strcmp( p, "ecjpake_pw" ) == 0 )
			opt.ecjpake_pw = q;
		else if( strcmp( p, "force_ciphersuite" ) == 0 )
		{
			opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id( q );

			if( opt.force_ciphersuite[0] == 0 )
			{
				ret = 2;
				goto usage;
			}
			opt.force_ciphersuite[1] = 0;
		}
		else if( strcmp( p, "renegotiation" ) == 0 )
		{
			opt.renegotiation = (atoi( q )) ? MBEDTLS_SSL_RENEGOTIATION_ENABLED :
											  MBEDTLS_SSL_RENEGOTIATION_DISABLED;
		}
		else if( strcmp( p, "allow_legacy" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case -1: opt.allow_legacy = MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE; break;
				case 0:  opt.allow_legacy = MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION; break;
				case 1:  opt.allow_legacy = MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION; break;
				default: goto usage;
			}
		}
		else if( strcmp( p, "renegotiate" ) == 0 )
		{
			opt.renegotiate = atoi( q );
			if( opt.renegotiate < 0 || opt.renegotiate > 1 )
				goto usage;
		}
		else if( strcmp( p, "exchanges" ) == 0 )
		{
			opt.exchanges = atoi( q );
			if( opt.exchanges < 1 )
				goto usage;
		}
		else if( strcmp( p, "reconnect" ) == 0 )
		{
			opt.reconnect = atoi( q );
			if( opt.reconnect < 0 || opt.reconnect > 2 )
				goto usage;
		}
		else if( strcmp( p, "reco_delay" ) == 0 )
		{
			opt.reco_delay = atoi( q );
			if( opt.reco_delay < 0 )
				goto usage;
		}
		else if( strcmp( p, "reconnect_hard" ) == 0 )
		{
			opt.reconnect_hard = atoi( q );
			if( opt.reconnect_hard < 0 || opt.reconnect_hard > 1 )
				goto usage;
		}
		else if( strcmp( p, "tickets" ) == 0 )
		{
			opt.tickets = atoi( q );
			if( opt.tickets < 0 || opt.tickets > 2 )
				goto usage;
		}
		else if( strcmp( p, "alpn" ) == 0 )
		{
			opt.alpn_string = q;
		}
		else if( strcmp( p, "fallback" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case 0: opt.fallback = MBEDTLS_SSL_IS_NOT_FALLBACK; break;
				case 1: opt.fallback = MBEDTLS_SSL_IS_FALLBACK; break;
				default: goto usage;
			}
		}
		else if( strcmp( p, "extended_ms" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case 0: opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_DISABLED; break;
				case 1: opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED; break;
				default: goto usage;
			}
		}
		else if( strcmp( p, "etm" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case 0: opt.etm = MBEDTLS_SSL_ETM_DISABLED; break;
				case 1: opt.etm = MBEDTLS_SSL_ETM_ENABLED; break;
				default: goto usage;
			}
		}
		else if( strcmp( p, "min_version" ) == 0 )
		{
			if( strcmp( q, "ssl3" ) == 0 )
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_0;
			else if( strcmp( q, "tls1" ) == 0 )
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_1;
			else if( strcmp( q, "tls1_1" ) == 0 ||
					 strcmp( q, "dtls1" ) == 0 )
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
			else if( strcmp( q, "tls1_2" ) == 0 ||
					 strcmp( q, "dtls1_2" ) == 0 )
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
			else
				goto usage;
		}
		else if( strcmp( p, "max_version" ) == 0 )
		{
			if( strcmp( q, "ssl3" ) == 0 )
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_0;
			else if( strcmp( q, "tls1" ) == 0 )
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_1;
			else if( strcmp( q, "tls1_1" ) == 0 ||
					 strcmp( q, "dtls1" ) == 0 )
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
			else if( strcmp( q, "tls1_2" ) == 0 ||
					 strcmp( q, "dtls1_2" ) == 0 )
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
			else
				goto usage;
		}
		else if( strcmp( p, "arc4" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case 0:     opt.arc4 = MBEDTLS_SSL_ARC4_DISABLED;   break;
				case 1:     opt.arc4 = MBEDTLS_SSL_ARC4_ENABLED;    break;
				default:    goto usage;
			}
		}
		else if( strcmp( p, "force_version" ) == 0 )
		{
			if( strcmp( q, "ssl3" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_0;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_0;
			}
			else if( strcmp( q, "tls1" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_1;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_1;
			}
			else if( strcmp( q, "tls1_1" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
			}
			else if( strcmp( q, "tls1_2" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
			}
			else if( strcmp( q, "dtls1" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_2;
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			}
			else if( strcmp( q, "dtls1_2" ) == 0 )
			{
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
				opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
			}
			else
				goto usage;
		}
		else if( strcmp( p, "auth_mode" ) == 0 )
		{
			if( strcmp( q, "none" ) == 0 )
				opt.auth_mode = MBEDTLS_SSL_VERIFY_NONE;
			else if( strcmp( q, "optional" ) == 0 )
				opt.auth_mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
			else if( strcmp( q, "required" ) == 0 )
				opt.auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
			else
				goto usage;
		}
		else if( strcmp( p, "max_frag_len" ) == 0 )
		{
			if( strcmp( q, "512" ) == 0 )
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_512;
			else if( strcmp( q, "1024" ) == 0 )
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_1024;
			else if( strcmp( q, "2048" ) == 0 )
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_2048;
			else if( strcmp( q, "4096" ) == 0 )
				opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_4096;
			else
				goto usage;
		}
		else if( strcmp( p, "trunc_hmac" ) == 0 )
		{
			switch( atoi( q ) )
			{
				case 0: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_DISABLED; break;
				case 1: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED; break;
				default: goto usage;
			}
		}
		else if( strcmp( p, "hs_timeout" ) == 0 )
		{
			if( ( p = strchr( q, '-' ) ) == NULL )
				goto usage;
			*p++ = '\0';
			opt.hs_to_min = atoi( q );
			opt.hs_to_max = atoi( p );
			if( opt.hs_to_min == 0 || opt.hs_to_max < opt.hs_to_min )
				goto usage;
		}
		else if( strcmp( p, "recsplit" ) == 0 )
		{
			opt.recsplit = atoi( q );
			if( opt.recsplit < 0 || opt.recsplit > 1 )
				goto usage;
		}
		else if( strcmp( p, "dhmlen" ) == 0 )
		{
			opt.dhmlen = atoi( q );
			if( opt.dhmlen < 0 )
				goto usage;
		}
		else
			goto usage;
	}

#if defined(MBEDTLS_DEBUG_C)
	mbedtls_debug_set_threshold( opt.debug_level );
#endif

	if( opt.force_ciphersuite[0] > 0 )
	{
		const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
		ciphersuite_info = mbedtls_ssl_ciphersuite_from_id( opt.force_ciphersuite[0] );

		if( opt.max_version != -1 &&
			ciphersuite_info->min_minor_ver > opt.max_version )
		{
			mbedtls_printf("forced ciphersuite not allowed with this protocol version\n");
			ret = 2;
			goto usage;
		}
		if( opt.min_version != -1 &&
			ciphersuite_info->max_minor_ver < opt.min_version )
		{
			mbedtls_printf("forced ciphersuite not allowed with this protocol version\n");
			ret = 2;
			goto usage;
		}

		/* If the server selects a version that's not supported by
		 * this suite, then there will be no common ciphersuite... */
		if( opt.max_version == -1 ||
			opt.max_version > ciphersuite_info->max_minor_ver )
		{
			opt.max_version = ciphersuite_info->max_minor_ver;
		}
		if( opt.min_version < ciphersuite_info->min_minor_ver )
		{
			opt.min_version = ciphersuite_info->min_minor_ver;
			/* DTLS starts with TLS 1.1 */
			if( opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
				opt.min_version < MBEDTLS_SSL_MINOR_VERSION_2 )
				opt.min_version = MBEDTLS_SSL_MINOR_VERSION_2;
		}

		/* Enable RC4 if needed and not explicitly disabled */
		if( ciphersuite_info->cipher == MBEDTLS_CIPHER_ARC4_128 )
		{
			if( opt.arc4 == MBEDTLS_SSL_ARC4_DISABLED )
			{
				mbedtls_printf("forced RC4 ciphersuite with RC4 disabled\n");
				ret = 2;
				goto usage;
			}

			opt.arc4 = MBEDTLS_SSL_ARC4_ENABLED;
		}
	}

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
	/*
	 * Unhexify the pre-shared key if any is given
	 */
	if( strlen( opt.psk ) )
	{
		unsigned char c;
		size_t j;

		if( strlen( opt.psk ) % 2 != 0 )
		{
			mbedtls_printf("pre-shared key not valid hex\n");
			goto exit;
		}

		psk_len = strlen( opt.psk ) / 2;

		for( j = 0; j < strlen( opt.psk ); j += 2 )
		{
			c = opt.psk[j];
			if( c >= '0' && c <= '9' )
				c -= '0';
			else if( c >= 'a' && c <= 'f' )
				c -= 'a' - 10;
			else if( c >= 'A' && c <= 'F' )
				c -= 'A' - 10;
			else
			{
				mbedtls_printf("pre-shared key not valid hex\n");
				goto exit;
			}
			psk[ j / 2 ] = c << 4;

			c = opt.psk[j + 1];
			if( c >= '0' && c <= '9' )
				c -= '0';
			else if( c >= 'a' && c <= 'f' )
				c -= 'a' - 10;
			else if( c >= 'A' && c <= 'F' )
				c -= 'A' - 10;
			else
			{
				mbedtls_printf("pre-shared key not valid hex\n");
				goto exit;
			}
			psk[ j / 2 ] |= c;
		}
	}
#endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */

#if defined(MBEDTLS_SSL_ALPN)
	if( opt.alpn_string != NULL )
	{
		p = (char *) opt.alpn_string;
		i = 0;

		/* Leave room for a final NULL in alpn_list */
		while( i < (int) sizeof alpn_list - 1 && *p != '\0' )
		{
			alpn_list[i++] = p;

			/* Terminate the current string and move on to next one */
			while( *p != ',' && *p != '\0' )
				p++;
			if( *p == ',' )
				*p++ = '\0';
		}
	}
#endif /* MBEDTLS_SSL_ALPN */

	/*
	 * 0. Initialize the RNG and the session data
	 */
	mbedtls_printf( "\n  . Seeding the random number generator..." );
	fflush( stdout );

	mbedtls_entropy_init( &entropy );
	if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
							   (const unsigned char *) pers,
							   strlen( pers ) ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ctr_drbg_seed returned -0x%x\n", -ret );
		goto exit;
	}

	mbedtls_printf( " ok\n" );

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	/*
	 * 1.1. Load the trusted CA
	 */
	mbedtls_printf( "  . Loading the CA root certificate ..." );
	fflush( stdout );

#if defined(MBEDTLS_FS_IO)
	if( strlen( opt.ca_path ) )
		if( strcmp( opt.ca_path, "none" ) == 0 )
			ret = 0;
		else
			ret = mbedtls_x509_crt_parse_path( &cacert, opt.ca_path );
	else if( strlen( opt.ca_file ) )
		if( strcmp( opt.ca_file, "none" ) == 0 )
			ret = 0;
		else
			ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file );
	else
#endif
#if defined(MBEDTLS_CERTS_C)
		for( i = 0; mbedtls_test_cas[i] != NULL; i++ )
		{
			ret = mbedtls_x509_crt_parse( &cacert,
								  (const unsigned char *) mbedtls_test_cas[i],
								  mbedtls_test_cas_len[i] );
			if( ret != 0 )
				break;
		}
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if( ret < 0 )
	{
		mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret );
		goto exit;
	}

	mbedtls_printf( " ok (%d skipped)\n", ret );

	/*
	 * 1.2. Load own certificate and private key
	 *
	 * (can be skipped if client authentication is not required)
	 */
	mbedtls_printf( "  . Loading the client cert. and key..." );
	fflush( stdout );

#if defined(MBEDTLS_FS_IO)
	if( strlen( opt.crt_file ) )
		if( strcmp( opt.crt_file, "none" ) == 0 )
			ret = 0;
		else
			ret = mbedtls_x509_crt_parse_file( &clicert, opt.crt_file );
	else
#endif
#if defined(MBEDTLS_CERTS_C)
		ret = mbedtls_x509_crt_parse( &clicert, (const unsigned char *) mbedtls_test_cli_crt,
				mbedtls_test_cli_crt_len );
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if( ret != 0 )
	{
		mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n", -ret );
		goto exit;
	}

#if defined(MBEDTLS_FS_IO)
	if( strlen( opt.key_file ) )
		if( strcmp( opt.key_file, "none" ) == 0 )
			ret = 0;
		else
			ret = mbedtls_pk_parse_keyfile( &pkey, opt.key_file, "" );
	else
#endif
#if defined(MBEDTLS_CERTS_C)
		ret = mbedtls_pk_parse_key( &pkey, (const unsigned char *) mbedtls_test_cli_key,
				mbedtls_test_cli_key_len, NULL, 0 );
#else
	{
		ret = 1;
		mbedtls_printf("MBEDTLS_CERTS_C not defined.");
	}
#endif
	if( ret != 0 )
	{
		mbedtls_printf( " failed\n  !  mbedtls_pk_parse_key returned -0x%x\n\n", -ret );
		goto exit;
	}

	mbedtls_printf( " ok\n" );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

	/*
	 * 2. Start the connection
	 */
	if( opt.server_addr == NULL)
		opt.server_addr = opt.server_name;

	mbedtls_printf( "  . Connecting to %s/%s/%s...",
			opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ? "tcp" : "udp",
			opt.server_addr, opt.server_port );
	fflush( stdout );

	if( ( ret = mbedtls_net_connect( &server_fd, opt.server_addr, opt.server_port,
							 opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
							 MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret );
		goto exit;
	}

	if( opt.nbio > 0 )
		ret = mbedtls_net_set_nonblock( &server_fd );
	else
		ret = mbedtls_net_set_block( &server_fd );
	if( ret != 0 )
	{
		mbedtls_printf( " failed\n  ! net_set_(non)block() returned -0x%x\n\n", -ret );
		goto exit;
	}

	mbedtls_printf( " ok\n" );

	/*
	 * 3. Setup stuff
	 */
	mbedtls_printf( "  . Setting up the SSL/TLS structure..." );
	fflush( stdout );

	if( ( ret = mbedtls_ssl_config_defaults( &conf,
					MBEDTLS_SSL_IS_CLIENT,
					opt.transport,
					MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ssl_config_defaults returned -0x%x\n\n", -ret );
		goto exit;
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if( opt.debug_level > 0 )
		mbedtls_ssl_conf_verify( &conf, my_verify, NULL );
#endif

	if( opt.auth_mode != DFL_AUTH_MODE )
		mbedtls_ssl_conf_authmode( &conf, opt.auth_mode );

#if defined(MBEDTLS_SSL_PROTO_DTLS)
	if( opt.hs_to_min != DFL_HS_TO_MIN || opt.hs_to_max != DFL_HS_TO_MAX )
		mbedtls_ssl_conf_handshake_timeout( &conf, opt.hs_to_min, opt.hs_to_max );
#endif /* MBEDTLS_SSL_PROTO_DTLS */

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
	if( ( ret = mbedtls_ssl_conf_max_frag_len( &conf, opt.mfl_code ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_max_frag_len returned %d\n\n", ret );
		goto exit;
	}
#endif

#if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
	if( opt.trunc_hmac != DFL_TRUNC_HMAC )
		mbedtls_ssl_conf_truncated_hmac( &conf, opt.trunc_hmac );
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
	if( opt.extended_ms != DFL_EXTENDED_MS )
		mbedtls_ssl_conf_extended_master_secret( &conf, opt.extended_ms );
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
	if( opt.etm != DFL_ETM )
		mbedtls_ssl_conf_encrypt_then_mac( &conf, opt.etm );
#endif

#if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
	if( opt.recsplit != DFL_RECSPLIT )
		mbedtls_ssl_conf_cbc_record_splitting( &conf, opt.recsplit
									? MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED
									: MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED );
#endif

#if defined(MBEDTLS_DHM_C)
	if( opt.dhmlen != DFL_DHMLEN )
		mbedtls_ssl_conf_dhm_min_bitlen( &conf, opt.dhmlen );
#endif

#if defined(MBEDTLS_SSL_ALPN)
	if( opt.alpn_string != NULL )
		if( ( ret = mbedtls_ssl_conf_alpn_protocols( &conf, alpn_list ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_alpn_protocols returned %d\n\n", ret );
			goto exit;
		}
#endif

	mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
	mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );

	mbedtls_ssl_conf_read_timeout( &conf, opt.read_timeout );

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
	mbedtls_ssl_conf_session_tickets( &conf, opt.tickets );
#endif

	if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
		mbedtls_ssl_conf_ciphersuites( &conf, opt.force_ciphersuite );

#if defined(MBEDTLS_ARC4_C)
	if( opt.arc4 != DFL_ARC4 )
		mbedtls_ssl_conf_arc4_support( &conf, opt.arc4 );
#endif

	if( opt.allow_legacy != DFL_ALLOW_LEGACY )
		mbedtls_ssl_conf_legacy_renegotiation( &conf, opt.allow_legacy );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
	mbedtls_ssl_conf_renegotiation( &conf, opt.renegotiation );
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if( strcmp( opt.ca_path, "none" ) != 0 &&
		strcmp( opt.ca_file, "none" ) != 0 )
	{
		mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL );
	}
	if( strcmp( opt.crt_file, "none" ) != 0 &&
		strcmp( opt.key_file, "none" ) != 0 )
	{
		if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &clicert, &pkey ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret );
			goto exit;
		}
	}
#endif

#if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
	if( ( ret = mbedtls_ssl_conf_psk( &conf, psk, psk_len,
							 (const unsigned char *) opt.psk_identity,
							 strlen( opt.psk_identity ) ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_psk returned %d\n\n", ret );
		goto exit;
	}
#endif

	if( opt.min_version != DFL_MIN_VERSION )
		mbedtls_ssl_conf_min_version( &conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.min_version );

	if( opt.max_version != DFL_MAX_VERSION )
		mbedtls_ssl_conf_max_version( &conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.max_version );

#if defined(MBEDTLS_SSL_FALLBACK_SCSV)
	if( opt.fallback != DFL_FALLBACK )
		mbedtls_ssl_conf_fallback( &conf, opt.fallback );
#endif

	if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ssl_setup returned -0x%x\n\n", -ret );
		goto exit;
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	if( ( ret = mbedtls_ssl_set_hostname( &ssl, opt.server_name ) ) != 0 )
	{
		mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n", ret );
		goto exit;
	}
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
	if( opt.ecjpake_pw != DFL_ECJPAKE_PW )
	{
		if( ( ret = mbedtls_ssl_set_hs_ecjpake_password( &ssl,
						(const unsigned char *) opt.ecjpake_pw,
										strlen( opt.ecjpake_pw ) ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hs_ecjpake_password returned %d\n\n", ret );
			goto exit;
		}
	}
#endif

	if( opt.nbio == 2 )
		mbedtls_ssl_set_bio( &ssl, &server_fd, my_send, my_recv, NULL );
	else
		mbedtls_ssl_set_bio( &ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv,
							 opt.nbio == 0 ? mbedtls_net_recv_timeout : NULL );

#if defined(MBEDTLS_TIMING_C)
	mbedtls_ssl_set_timer_cb( &ssl, &timer, mbedtls_timing_set_delay,
											mbedtls_timing_get_delay );
#endif

	mbedtls_printf( " ok\n" );

	/*
	 * 4. Handshake
	 */
	mbedtls_printf( "  . Performing the SSL/TLS handshake..." );
	fflush( stdout );

	while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
	{
		if( ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n", -ret );
			if( ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED )
				mbedtls_printf(
					"    Unable to verify the server's certificate. "
						"Either it is invalid,\n"
					"    or you didn't set ca_file or ca_path "
						"to an appropriate value.\n"
					"    Alternatively, you may want to use "
						"auth_mode=optional for testing purposes.\n" );
			mbedtls_printf( "\n" );
			goto exit;
		}
	}

	mbedtls_printf( " ok\n    [ Protocol is %s ]\n    [ Ciphersuite is %s ]\n",
			mbedtls_ssl_get_version( &ssl ), mbedtls_ssl_get_ciphersuite( &ssl ) );

	if( ( ret = mbedtls_ssl_get_record_expansion( &ssl ) ) >= 0 )
		mbedtls_printf( "    [ Record expansion is %d ]\n", ret );
	else
		mbedtls_printf( "    [ Record expansion is unknown (compression) ]\n" );

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
	mbedtls_printf( "    [ Maximum fragment length is %u ]\n",
					(unsigned int) mbedtls_ssl_get_max_frag_len( &ssl ) );
#endif

#if defined(MBEDTLS_SSL_ALPN)
	if( opt.alpn_string != NULL )
	{
		const char *alp = mbedtls_ssl_get_alpn_protocol( &ssl );
		mbedtls_printf( "    [ Application Layer Protocol is %s ]\n",
				alp ? alp : "(none)" );
	}
#endif

	if( opt.reconnect != 0 )
	{
		mbedtls_printf("  . Saving session for reuse..." );
		fflush( stdout );

		if( ( ret = mbedtls_ssl_get_session( &ssl, &saved_session ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_get_session returned -0x%x\n\n", -ret );
			goto exit;
		}

		mbedtls_printf( " ok\n" );
	}

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	/*
	 * 5. Verify the server certificate
	 */
	mbedtls_printf( "  . Verifying peer X.509 certificate..." );

	if( ( flags = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 )
	{
		char vrfy_buf[512];

		mbedtls_printf( " failed\n" );

		mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), "  ! ", flags );

		mbedtls_printf( "%s\n", vrfy_buf );
	}
	else
		mbedtls_printf( " ok\n" );

	if( mbedtls_ssl_get_peer_cert( &ssl ) != NULL )
	{
		mbedtls_printf( "  . Peer certificate information    ...\n" );
		mbedtls_x509_crt_info( (char *) buf, sizeof( buf ) - 1, "      ",
					   mbedtls_ssl_get_peer_cert( &ssl ) );
		mbedtls_printf( "%s\n", buf );
	}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_RENEGOTIATION)
	if( opt.renegotiate )
	{
		/*
		 * Perform renegotiation (this must be done when the server is waiting
		 * for input from our side).
		 */
		mbedtls_printf( "  . Performing renegotiation..." );
		fflush( stdout );
		while( ( ret = mbedtls_ssl_renegotiate( &ssl ) ) != 0 )
		{
			if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
				ret != MBEDTLS_ERR_SSL_WANT_WRITE )
			{
				mbedtls_printf( " failed\n  ! mbedtls_ssl_renegotiate returned %d\n\n", ret );
				goto exit;
			}
		}
		mbedtls_printf( " ok\n" );
	}
#endif /* MBEDTLS_SSL_RENEGOTIATION */

	/*
	 * 6. Write the GET request
	 */
	retry_left = opt.max_resend;
send_request:
	mbedtls_printf( "  > Write to server:" );
	fflush( stdout );

	len = mbedtls_snprintf( (char *) buf, sizeof(buf) - 1, GET_REQUEST,
					opt.request_page );
	tail_len = (int) strlen( GET_REQUEST_END );

	/* Add padding to GET request to reach opt.request_size in length */
	if( opt.request_size != DFL_REQUEST_SIZE &&
		len + tail_len < opt.request_size )
	{
		memset( buf + len, 'A', opt.request_size - len - tail_len );
		len += opt.request_size - len - tail_len;
	}

	strncpy( (char *) buf + len, GET_REQUEST_END, sizeof(buf) - len - 1 );
	len += tail_len;

	/* Truncate if request size is smaller than the "natural" size */
	if( opt.request_size != DFL_REQUEST_SIZE &&
		len > opt.request_size )
	{
		len = opt.request_size;

		/* Still end with \r\n unless that's really not possible */
		if( len >= 2 ) buf[len - 2] = '\r';
		if( len >= 1 ) buf[len - 1] = '\n';
	}

	if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
	{
		for( written = 0, frags = 0; written < len; written += ret, frags++ )
		{
			while( ( ret = mbedtls_ssl_write( &ssl, buf + written, len - written ) )
						   <= 0 )
			{
				if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
					ret != MBEDTLS_ERR_SSL_WANT_WRITE )
				{
					mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned -0x%x\n\n", -ret );
					goto exit;
				}
			}
		}
	}
	else /* Not stream, so datagram */
	{
		do ret = mbedtls_ssl_write( &ssl, buf, len );
		while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
			   ret == MBEDTLS_ERR_SSL_WANT_WRITE );

		if( ret < 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned %d\n\n", ret );
			goto exit;
		}

		frags = 1;
		written = ret;
	}

	buf[written] = '\0';
	mbedtls_printf( " %d bytes written in %d fragments\n\n%s\n", written, frags, (char *) buf );

	/*
	 * 7. Read the HTTP response
	 */
	mbedtls_printf( "  < Read from server:" );
	fflush( stdout );

	/*
	 * TLS and DTLS need different reading styles (stream vs datagram)
	 */
	if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
	{
		do
		{
			len = sizeof( buf ) - 1;
			memset( buf, 0, sizeof( buf ) );
			ret = mbedtls_ssl_read( &ssl, buf, len );

			if( ret == MBEDTLS_ERR_SSL_WANT_READ ||
				ret == MBEDTLS_ERR_SSL_WANT_WRITE )
				continue;

			if( ret <= 0 )
			{
				switch( ret )
				{
					case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
						mbedtls_printf( " connection was closed gracefully\n" );
						ret = 0;
						goto close_notify;

					case 0:
					case MBEDTLS_ERR_NET_CONN_RESET:
						mbedtls_printf( " connection was reset by peer\n" );
						ret = 0;
						goto reconnect;

					default:
						mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n", -ret );
						goto exit;
				}
			}

			len = ret;
			buf[len] = '\0';
			mbedtls_printf( " %d bytes read\n\n%s", len, (char *) buf );

			/* End of message should be detected according to the syntax of the
			 * application protocol (eg HTTP), just use a dummy test here. */
			if( ret > 0 && buf[len-1] == '\n' )
			{
				ret = 0;
				break;
			}
		}
		while( 1 );
	}
	else /* Not stream, so datagram */
	{
		len = sizeof( buf ) - 1;
		memset( buf, 0, sizeof( buf ) );

		do ret = mbedtls_ssl_read( &ssl, buf, len );
		while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
			   ret == MBEDTLS_ERR_SSL_WANT_WRITE );

		if( ret <= 0 )
		{
			switch( ret )
			{
				case MBEDTLS_ERR_SSL_TIMEOUT:
					mbedtls_printf( " timeout\n" );
					if( retry_left-- > 0 )
						goto send_request;
					goto exit;

				case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
					mbedtls_printf( " connection was closed gracefully\n" );
					ret = 0;
					goto close_notify;

				default:
					mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n", -ret );
					goto exit;
			}
		}

		len = ret;
		buf[len] = '\0';
		mbedtls_printf( " %d bytes read\n\n%s", len, (char *) buf );
		ret = 0;
	}

	/*
	 * 7b. Simulate hard reset and reconnect from same port?
	 */
	if( opt.reconnect_hard != 0 )
	{
		opt.reconnect_hard = 0;

		mbedtls_printf( "  . Restarting connection from same port..." );
		fflush( stdout );

		if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n", -ret );
			goto exit;
		}

		while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
		{
			if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
				ret != MBEDTLS_ERR_SSL_WANT_WRITE )
			{
				mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret );
				goto exit;
			}
		}

		mbedtls_printf( " ok\n" );

		goto send_request;
	}

	/*
	 * 7c. Continue doing data exchanges?
	 */
	if( --opt.exchanges > 0 )
		goto send_request;

	/*
	 * 8. Done, cleanly close the connection
	 */
close_notify:
	mbedtls_printf( "  . Closing the connection..." );
	fflush( stdout );

	/* No error checking, the connection might be closed already */
	do ret = mbedtls_ssl_close_notify( &ssl );
	while( ret == MBEDTLS_ERR_SSL_WANT_WRITE );
	ret = 0;

	mbedtls_printf( " done\n" );

	/*
	 * 9. Reconnect?
	 */
reconnect:
	if( opt.reconnect != 0 )
	{
		--opt.reconnect;

		mbedtls_net_free( &server_fd );

#if defined(MBEDTLS_TIMING_C)
		if( opt.reco_delay > 0 )
			mbedtls_net_usleep( 1000000 * opt.reco_delay );
#endif

		mbedtls_printf( "  . Reconnecting with saved session..." );

		if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n", -ret );
			goto exit;
		}

		if( ( ret = mbedtls_ssl_set_session( &ssl, &saved_session ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_session returned %d\n\n", ret );
			goto exit;
		}

		if( ( ret = mbedtls_net_connect( &server_fd, opt.server_addr, opt.server_port,
								 opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
								 MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP ) ) != 0 )
		{
			mbedtls_printf( " failed\n  ! mbedtls_net_connect returned -0x%x\n\n", -ret );
			goto exit;
		}

		if( opt.nbio > 0 )
			ret = mbedtls_net_set_nonblock( &server_fd );
		else
			ret = mbedtls_net_set_block( &server_fd );
		if( ret != 0 )
		{
			mbedtls_printf( " failed\n  ! net_set_(non)block() returned -0x%x\n\n",
					-ret );
			goto exit;
		}

		while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
		{
			if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
				ret != MBEDTLS_ERR_SSL_WANT_WRITE )
			{
				mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret );
				goto exit;
			}
		}

		mbedtls_printf( " ok\n" );

		goto send_request;
	}

	/*
	 * Cleanup and exit
	 */
exit:
#ifdef MBEDTLS_ERROR_C
	if( ret != 0 )
	{
		char error_buf[100];
		mbedtls_strerror( ret, error_buf, 100 );
		mbedtls_printf("Last error was: -0x%X - %s\n\n", -ret, error_buf );
	}
#endif

	mbedtls_net_free( &server_fd );

#if defined(MBEDTLS_X509_CRT_PARSE_C)
	mbedtls_x509_crt_free( &clicert );
	mbedtls_x509_crt_free( &cacert );
	mbedtls_pk_free( &pkey );
#endif
	mbedtls_ssl_session_free( &saved_session );
	mbedtls_ssl_free( &ssl );
	mbedtls_ssl_config_free( &conf );
	mbedtls_ctr_drbg_free( &ctr_drbg );
	mbedtls_entropy_free( &entropy );

#if defined(_WIN32)
	mbedtls_printf( "  + Press Enter to exit this program.\n" );
	fflush( stdout ); getchar();
#endif

	// Shell can not handle large exit numbers -> 1 for errors
	if( ret < 0 )
		ret = 1;

	return( ret );
}
#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C && MBEDTLS_SSL_TLS_C &&
		  MBEDTLS_SSL_CLI_C && MBEDTLS_NET_C && MBEDTLS_RSA_C &&
		  MBEDTLS_CTR_DRBG_C MBEDTLS_TIMING_C */
